Continuous coating apparatus for electroceramic coating of cable

ABSTRACT

A system and a process for continuously electrolytically coating a wire, useful for a high tension cable, is provided. The system includes a bath containing a precursor for an electro-ceramic coating on a wire and containing a cathodic connection, at least one motor connected to at least one motive assembly to impart movement to the wire. A power source provides high voltage and high current to the wire through the electrification device, and through the wire in the bath to the cathode connection via the aqueous electrolytic solution. The process includes electrifying bare wire with a high voltage and a high current, passing the electrified bare wire through a bath having a cathodic connection and containing an aqueous solution with a precursor for an electro-ceramic coating, and electrochemically reacting the wire with the precursor thereby generating a coated wire having an electro-ceramic coating on at least one surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application Ser.No. 62/034,358 filed Aug. 7, 2014 and U.S. provisional application Ser.No. 62/034,308 filed Aug. 7, 2014, the disclosures of which are herebyincorporated in their entirety by reference herein.

TECHNICAL FIELD

Various embodiments relate to an apparatus and a process for coatingwires, as well as wires coated thereby, useful in high tension cablesand assembling the cables.

BACKGROUND

Power transmission and utility distribution systems for electricityinclude overhead cables carrying electricity at high tension voltage,e.g. greater than 100 kV, etc. in alternating current (AC) or directcurrent (DC), for distribution and transmission. Each cable is a bundleof multiple wires. A cable is two or more wires running side by side andbonded, twisted, or braided together to form a single assembly. Theseconductive wires are often made from or include elemental aluminum metaland/or an aluminum alloy. Desirable performance requirements for cablesfor overhead power transmission applications include corrosionresistance, environmental endurance (e.g., UV and moisture), resistanceto loss of strength at elevated temperatures, creep resistance, as wellas relatively high elastic modulus, low density, low coefficient ofthermal expansion, high electrical conductivity and high strength.

The aluminum transmission cables are often bare or uncoated, act asconductors of electricity that tend to operate at a high temperature,for example, approximately 60-160 degrees Celsius, and generally havepoor emissivity. These features are a drawback in conductors sinceresistivity of conductors generally increases with increasingtemperature. The hot aluminum cable has phonon vibrations that in turncause additional Joule heating or resistive heating. Emissivity (ε) isthe ability of a surface to emit radiation energy compared to a blackbody at the same temperature and is expressed as a ratio of theradiation emitted by the surface to that emitted by the black body(scale is 0 to 1, with lower numbers indicating poorer emissivity andnumbers approaching 1 indicating good emissivity). The emissivity ofconventional uncoated aluminum wire and cable in use is generally in therange of about 0.05-0.10. Thus there is a need for aluminum conductorwire having improved emissivity and a need for methods of making thesewires.

Users of overhead utility transmission cable, e.g. power companies andpublic utilities, experience large energy losses caused by the cable asthe operating temperature of the cable increases because resistivity ofconductors generally increases with increasing temperature. This energyloss is estimated to account for billions in expenses annually throughloss of generated power as it moves through electrical supply lines,also known as “the grid”. For example, a typical electrically loadedcable operates under load at a temperature starting from externalenvironmental temperature (e.g. −65 degrees Celsius to about +50 degreesCelsius) and increases up to about 180 degrees Celsius. The conventionaluncoated aluminum overhead utility transmission cables have energylosses through excessive Joule heating as the cable operatingtemperature increases. The Joule heating losses from an uncoated cablemay exceed 25% of the power generated, depending on grid size.Additionally, as the temperature of aluminum cable increases, the cablealso sags downward with the force of gravity which may cause a hazard.This sag phenomenon requires increasing strength of the cable, generallyby including heavy steel wire in the cable's core, and the use of heavyhardware and towers to hold the cable and secure it at a safe distanceto eliminate issues relating to grounding and electrically shorting outthe cable. Although overhead power transmission cables includingaluminum wires are known, for some applications there is a continuingdesire, for example, for more desirable sag properties.

Conventional bare cable has been previously coated using other coatingssuch as paints, etc., see for example WO2014025420, and cathodic platingof a dissimilar metal layer onto a metal wire; however, these coatingswere limited in flexibility and long term adhesion on the cable suchthat the coating had a low durability. Thus a need remains for durable,high emissivity coatings on wire and cable, and methods and apparatusfor manufacturing the coated wire and cable.

SUMMARY

The apparatus and process for electro-ceramic coating provides forcontinuous coating of a wire for use in high tension cable. Theelectrification device in the apparatus, such as a rotating electricalconnector, e.g. an electrical slip ring, brushed or brushless, or aliquid mercury rotary contact; or a non-rotating dry anode connection,e.g. an aluminum or copper contact surface; provides the wire with ahigh voltage and a high current within a bath of liquid precursor, whichin turn causes an electrochemical reaction with the surface of the wirewithin the bath to form the coating.

As used herein “high voltage” used in the coating apparatus and processincludes peak voltage potential of at least about 140 volts up to about800 volts; “high current” as used herein includes effective current ofat least about 20 amps and up to about 1000 amps per wire. These valuesmay be varied while practicing the continuous coating process withinpower applied ranges of at least 10, 20, 30, 40 or 50 kW per wire.Greater kW may be applied to a wire provided the wire has great enoughcross-sectional area to withstand the added kW without damage to thewire.

In one embodiment, the coating comprises aluminum, titanium, oxygen andphosphorus. In another embodiment, the coating comprises aluminum,titanium, zirconium, oxygen and, optionally phosphorus.

Any frame supporting and guiding the wire through the bath may be madeof an electrically insulating material to reduce overall energy use bythe apparatus and to prevent arcing. The motor driving the wire throughthe bath may also be insulated to protect the motor from the electrifiedwire.

Various embodiments of the present disclosure have associated,non-limiting advantages. For example, the electro-ceramic coating on theouter strands or wires of the cable provides for increased emissivity ofthe cable and lower cable operating temperatures. By lowering the cableoperating temperature, the losses from the cable incurred by Jouleheating are reduced, and the cable sag is reduced. Also, by operatingthe cable at a lower temperature, the cable is able to transmit the sameamount of electrical power as an uncoated cable more efficiently, orgreater amounts of electrical power at the same operating temperature asthe uncoated cable.

Other than in the operating examples, or where otherwise indicated, allnumbers expressing quantities of ingredients, reaction conditions, ordefining ingredient parameters used herein are to be understood asmodified in all instances by the tem “about”. Throughout thedescription, unless expressly stated to the contrary: percent, “partsof”, and ratio values are by weight or mass; the description of a groupor class of materials as suitable or preferred for a given purpose inconnection with the invention implies that mixtures of any two or moreof the members of the group or class are equally suitable or preferred;description of constituents in chemical terms refers to the constituentsat the time of addition to any combination specified in the descriptionor of generation in situ within the composition by chemical reaction(s)between one or more newly added constituents and one or moreconstituents already present in the composition when the otherconstituents are added; specification of constituents in ionic formadditionally implies the presence of sufficient counterions to produceelectrical neutrality for the composition as a whole and for anysubstance added to the composition; any counterions thus implicitlyspecified preferably are selected from among other constituentsexplicitly specified in ionic form, to the extent possible; otherwise,such counterions may be freely selected, except for avoiding counterionsthat act adversely to an object of the invention; molecular weight (MW)is weight average molecular weight; the word “mole” means “gram mole”,and the word itself and all of its grammatical variations may be usedfor any chemical species defined by all of the types and numbers ofatoms present in it, irrespective of whether the species is ionic,neutral, unstable, hypothetical or in fact a stable neutral substancewith well-defined molecules; and the terms “solution”, “soluble”, andthe like are to be understood as including not only true equilibriumsolutions but also dispersions that show no visually detectable tendencytoward phase separation over a period of observation of at least 100, orpreferably at least 1000, hours during which the material ismechanically undisturbed and the temperature of the material ismaintained at ambient room temperatures (18 to 25° Celsius). Thechemical precursors used for forming the high emissivity coating arepreferably free of the following chemicals: chromium, cyanide, nitriteions, oxalates; carbonates; silicon, e.g. siloxanes, organosiloxanes,silanes, silicate; hydroxylamines, sodium and sulfur. Specifically, itis increasingly preferred in the order given, independently for eachpreferably minimized component listed below, that precursor for theelectro-ceramic coating according to the invention, when directlycontacted with metal in a process according to this invention, containno more than 1.0, 0.35, 0.10, 0.08, 0.04, 0.02, 0.01, 0.001, or 0.0002percent of each of the following constituents: chromium, cyanide,nitrite ions; oxalates; carbonates; silicon, e.g. siloxanes,organosiloxanes, silanes, silicate; hydroxylamines, sodium and sulfur.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic showing a cable according to anembodiment in use;

FIG. 2 illustrates a cutaway view of a section of a cable according toan embodiment;

FIG. 3 illustrates a flow chart for one embodiment of a process ofassembling a cable and coating a wire;

FIG. 4 illustrates a schematic of an apparatus for coating a wireaccording to an embodiment;

FIG. 5 illustrates a schematic of a system or apparatus for coating awire according to another embodiment; and

FIG. 6 illustrates a schematic of a system or apparatus for coating awire according to yet another embodiment.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

FIG. 1 illustrates a schematic of an electrical system 10 fromgeneration to point of use. Electricity is generated at a power station,such as a coal-fired plant, a nuclear plant, a hydroelectric plant orthe like. Electricity is conducted from the plant 12 and typically maybe directed to a step-up transformer 14. The step-up transformer 14increases the voltage of the electricity. A power transmission system 16is electrically connected to the transformer 14 and includes hightension cables 18. An example of a cable 18 produced according to theinvention is illustrated in FIG. 2. The power transmission system 16 ofFIG. 1 may include both transmission apparatus and devices fordistribution of electricity in the power grid and operates at varioushigh tension voltages, i.e. 100 kV, 800 kV, etc. The cables 18 aresupported to keep them above the ground, generally by towers 20. Thecables 18 are bundles of conductive wire, such as aluminum, andaccording to an embodiment, are coated with an emissive material such asa ceramic material, and may have an emissivity in the range of 0.5 to0.9. Conventional cables are bare or uncoated such that the bare metalsurface of the cable is directly exposed to the environment, and air isused as the insulating material. The conventional cables have a lowemissivity, on the order of 0.05 to 0.10.

The power transmission system 16 is connected to one or more step downtransformers 22 that lower the voltage of the electricity for use inheavy and light industry 24, 26, commercial, and residentialdestinations 28.

Generally, energy losses are incurred as the operating temperature ofthe cable 18 in the system 16 increases. Using conventional cables, thelosses in the system 16 and grid may be measured in billions of U.S.dollars. Also, as the operating temperature of the cable increases, thecable may sag or droop, which may cause a hazard. The conventional cableneeds to be strengthened, and towers 20 and connecting hardware for thecables are used to hold the cable and secure it at a safe distance toreduce or eliminate issues relating to grounding and shorting out thecable.

As the coated cable 18 is exposed to solar insolation, or incident solarradiation 30, energy is transferred to the cable 18. The cable is alsogenerating an amount of heat based on phonon vibrations and Jouleheating. By increasing the emissivity of the cable, the heat lost fromthe cable via radiation heat transfer and emission 32 is increased,thereby lowering the overall operating temperature of the coated cable18 compared to an uncoated cable. The coated cable then maintains alower temperature under amp loading (current) as well as provides blackbody radiation to remove heat from the surface of the wire moreeffectively than a wire that is lower in emissivity or a bare wire. Aconventional uncoated cable operates under electrical load at atemperature up to approximately 180 degrees Celsius. A coated cable 18may operate at the same electrical loading at a temperature up to 30%lower. This allows for the coated cable 18 to either have reduced energylosses or an increase in the ampacity that a cable is able to withstand.

An example of a cable 18 is illustrated in FIG. 2. The cable 18 includeswires or strands 40. There are multiple layers 42 of wires 40 in thecable 18. All of the wires 40 in the cable may be made of aluminum, analuminum alloy, or another suitable lightweight conductive material. Inan alternative embodiment, as shown, a portion of the wires 40 in thecable, such as central wires 44, may be made of a support material, suchas steel, to provide additional strength to the cable. Although thewires 40 are shown as having a circular cross-section, other crosssections may be used as are known in the art, including trapezoidal, andthe like. The cable 18 may contain wires 40 having a common diameter, ormay contain wires of varying diameters. Any number of layers 42 may beused with the cable 18 including more or less layers than shown in FIG.2. The cable 18 may or may not contain steel or strengthening wires 44,and the wires 44 may be located in the central region as shown, orotherwise distributed throughout the cable in one or more layers, andmay by in a mixed layer of containing both steel and aluminum wires.

In the example shown in FIG. 2, the wires 40 in the outer layer 46 arecoated with the electro-ceramic coating 48 or another suitable coating.The coating 48 is in direct contact with the underlying bare aluminum oraluminum alloy wire and is also exposed to environment. In otherembodiments, the inner aluminum wires 40 may also be coated. The coating48 has a higher emissivity than the metal of the outer layer wires 46,such as aluminum, and may be a different color. In one embodiment, theemissivity of an electroceramic coated cable according to the inventionmay be at least 0.4, 0.5, 0.6, 0.7 or greater, which is at least tentimes greater in emissivity compared to bare aluminum.

By coating outer layer wires 46 in the cable 18, the emissivity of thecable is increased. Also, the surface area of the wires and cable isincreased. A wire having electro-ceramic coating deposited thereon mayhave a specific surface area that is 10 times to 250 times the specificsurface area of the uncoated wire, based upon BET measurement accordingto ASTM C1274-12. A specific surface area is the total surface area perunit mass (m²/g). The increased surface area provides for increasedradiative emission from the cable, as well as improved convectivecooling. According to one example, the electro-ceramic coating increasesthe specific surface area of a wire by one to two orders of magnitude,i.e. ten times to one hundred times. Desirably, the increase in surfacearea is at least a factor of 10, 20, 30, 40, 50, 60, 70, 80, 90, 100,120, 130, 140, 150 or 200 times that of the uncoated wire, and in oneexample the increase is surface area is in the range of 100 to 1000times that of the uncoated wire. In some embodiments, the surface areais less than 1000, 700, 500, 400, 350, 300, 250, or 225 times greaterthan the surface area of the underlying coated wire, e.g. than that of abare wire. A wire having electro-ceramic coating deposited thereon mayhave a surface area that is about 10, 20, 30, 40, 50, 60, 70, 80, 90,100, 120, 130, 140, 150, 170, or 200 times greater than the surface areaof the underlying coated wire and less than 1000, 700, 500, 400, 350,300, 250, or 225 times greater than the surface area of the underlyingcoated wire. In one example, the specific surface area is 700 times thatof the specific surface area of the uncoated wire. In a further example,the specific surface area was 140-700 times that of the specific surfacearea of the uncoated wire, based on BET measurement, and has an add-onmass of 800 mg/m².

The coating causes the cable to have a lower temperature than aconventional energized cable where both are operating under the sameelectrical load at a temperature up to about 150-180 degrees Celsius,e.g. approximately 160 degrees Celsius. The coated cable may showtemperatures of 20, 30, 40, 50, 60, 70, 80 or 100 degrees Celsius lowerin temperature than a similar cable having no coating. Theelectro-ceramic coated cable can operate up to 10%, 20% or 30% or morelower in temperature than the uncoated cable based on the same load, anddesirably operates at temperatures lower than the uncoated cable of atleast 1, 3, 5, 7 or 9%. This can provide the benefit of allowing eitherreduced energy losses from the coated cable, or the ability to increasethe current carrying capability of a given cable for a giventemperature.

It is desirable that the aluminum or aluminum alloy wire used in thecable 18 be continuously coated with an electro-ceramic or other highemissivity UV stable coating. The coating may be applied on wires whichwill form at least one or more of the most exterior set of wires (outerwires) surrounding a center core of wires (core wires) or may be appliedto an already assembled cable comprising one or more layers of wire,e.g. outer wires, outer core wires, inner core wires and a center wire.

The coating may be applied during a continuous process to individualwires before the wires are bundled into the cable. “Continuous” and“continuously” as used herein are meant to include processes that do notinvolve batch coating, such as where all or more than 50% of a wire tobe coated is in contact with the electrolyte at one time. By way ofnon-limiting example, a continuous wire coating process may include aprocess in which a feed wire to be coated is supplied to the electrolytebath by passing the wire through the bath. In an example, a continuousprocess includes processes wherein the product intended to be coated,aluminum wire for example, is passed in a continuous manner into a bathof the electrolyte and the coated wire exits the electrolyte, preferablyentry and egress of the wire from the bath may be at the same rate. Theleading end of one wire may be attached to the trailing end of the wireahead of it in the processing line. With the use of an accumulator,which may store up to perhaps 1000 ft. or more of wire ahead of the mainsection of the processing line, these wire ends can be joined withoutstopping the main section provided that adequate protection is providedagainst the current running through the electrolyte and the electrifiedwire. As a result, the wire being processed through the coating bathneed not stop and the process is truly “continuous.” Continuousprocesses may include intermittent stoppages, by way of non-limitingexample for changing of wire spools or maintenance, or besemi-continuous, i.e. continuous manufacturing, but for a discrete timeperiod, without going outside of the scope of the invention.

Advantages of continuous coating of wire include integrated processingwith fewer steps; little or no manual handling of the wire; increasedsafety; shorter processing times; increased efficiency; smaller coatingbaths and hence less energy consumption and facility space used; a moreflexible operation with lower capital costs; smaller ecologicalfootprint; on-line monitoring and control for increased product qualityassurance in real-time; and a potential for reduced costs.

In one example, the outermost layer wires 46 in the cable 18 are coatedprior to the bundling process to form the finished cable 18. The outerlayer wires 46 are singly coated and then placed as the outer wires onthe cable 18, thereby only coating the wires 40 that gain the mostbenefit from having a high emissivity coating on them, i.e. the wiresexposed to the external environment. Alternatively, the entire cable maybe coated after the bundling process. While, this aspect may provideonly minor improvement in cable efficiency or operating temperature overcable with only the outer wires coated, having all aluminum surfaces ofthe cable that can be reached by the aqueous electrolyte coated can beuseful in retrofit applications or where cable winding equipment isincompatible with the electro-ceramic coated wire. The greateremissivity coating may also allow for reduced sag of a finished cable ofsame design due to the reduced operating temperature.

High surface area coatings 48, meaning those coatings with a unitsurface are of more than five times that of the unit surface area of theunderlying wire, that also have higher emissivity than the bare wire maybe useful in cooling the wire by reducing the phonon vibrations therebyproviding a reduction in overall Joule heating. This may effectivelysave on the order of tens of thousands of dollars in wasted electricityper installed mile of high tension cable per year. Alternatively, thecoated cable may be used to transmit greater current levels than aconventional cable at the same operating temperature, thereby providingfor increased power transmission and the ability to effectively increasethe maximum power throughput of the cable and grid without introducingadditional cable. The coatings are typically stable in ultraviolet (UV)light to withstand exposure to the sun. Additionally, the coatings maybe scratch resistant, and may be able to bend with the cable 18 or outerlayer wire 46 without cracking, delaminating or breaking. The coatingsmay be thin such that they do not significantly increase the overallweight of the cable. In one example, the coatings may be five to twentymicrons in thickness, and may be in the range of ten to fifteen microns,five to ten microns, or eight to twelve microns in further examples.

For example, an electro-ceramic coating 48 may be applied to aluminumouter layer wire 46 that would normally be bare or uncoated on a hightension transmission cable 18 operating at approximately at 100-700 kV.Enhanced emissivity, enhanced surface area, UV stability, and goodthermal conductivity are desirable characteristics for the coating 48.

Note that wires having higher emissivity than bare wire with low solarabsorption may be useful in many high tension electrical transmissionapplication areas where voltage being transmitted is about 10 kVolts ormore. By practicing the methods of the invention, the shade or color ofthe coating may be varied, for example, by various shades of greyranging from white to black, with lighter shades of grey providing lowerabsorption of solar emissions. Darker shades of grey may be used to helpthe cable shed ice for example.

The coating 48 on the wire may be a uniform coating having a constant orgenerally constant thickness about the perimeter of the outer layer wire46. Desirably, this uniformity is achieved in the absence of apolishing, grinding or other removal of coating. In one embodiment,thickness may vary by 0 to 25%, for example at least 1, 3, 5, 7, 9 or10%, and desirably no more than 25, 20, 18, 16, 14, or 12%, with highertolerances being acceptable with thicker coatings. The coating 48provides for improved emissivity, surface area and heat transfercompared to a bare wire. The coating 48 on the wire has beendemonstrated to pass a T-bend test of 0T-1T showing a high bend strengthand high adhesion to the outer layer wire 46 to provide flexibilityunder weathering conditions and subjected forces during use. In oneexample, the emissivity of the coating ranges from about 0.5, 0.6 to1.00, and in a further example, the emissivity is from 0.6 to 0.96.

In an alternative embodiment, knurling or rifling of the outer surfaceof the outer layer wires 46 may be also implemented before coating tofurther increase the surface area of the coating to improve heattransfer. In addition, secondary heat transfer fins such as spine fins,or fins that have a high surface area and are an adhesively bondedauxiliary fin, may be adhesively bonded to the cable 18 or outer layerwire 46 for additional surface area enhancement. These secondary heattransfer fins may also be coated.

Various high emissivity coatings may be deposited using the methods andapparatus described in the present disclosure. An example of anelectro-ceramic coating for use as the coating 48 and the associatedchemistry, including reactants, to use when generating the coating on alight metal substrate such as aluminum or an aluminum alloy is describedin U.S. Pat. No. 6,797,147 issued on Sep. 28, 2004; U.S. Pat. No.6,916,414 issued on Jul. 12, 2005; and U.S. Pat. No. 7,578,921 issued onAug. 25, 2009; the disclosures of which are incorporated in theirentirety by reference herein.

FIG. 3 illustrates an exemplary flow chart for a process or method formanufacturing coated wire and a cable made therefrom according to oneembodiment. In other embodiments, the process may include a greater orfewer number of steps, and various steps may be performed sequentiallyor in parallel with one another. The steps in the process may also beordered differently from the illustrated flow chart in otherembodiments.

Referring to FIG. 3, in step 60, metal is formed into wire; this is anoptional step in the process. Starting with a metal workpiece, anextrusion process, drawing process, or other metal-forming process maybe used to generate a bare wire. The process may be cold or hot, basedon the material used and the desired properties. In a typical wiregenerating process, a metal rod having a first diameter is drawn througha die thereby generating a wire having a second diameter less than thediameter of the metal rod. This step may be repeated, drawing the wirerod through a series of dies, with or without spooling between dies,until the desired final diameter of the wire is achieved. The producedwire product is generally wound around a spool for ease of handling. Themetal may be subjected to additional treatments, including tempering,annealing, and the like before, during and/or after the process by whichthe wire is generated from the metal workpiece. In one example, the wiremay be aluminum or an aluminum alloy.

Alternatively, step 60 may comprise obtaining commercially availablebare aluminum wire of desired geometry and providing same to the coatingline.

In processes according to the invention, bare wire may be provided on aspool, reel or other wire carrier, which may be used to feed wire intothe coating process. Desirably, the wire carrier for feeding the barewire into the coating process comprises a spool, reel or the like aboutwhich the bare wire is wound. Bare wire will be understood by those ofskill in the art to mean wire having surfaces of metallic aluminum or analuminum alloy in the absence of a durable applied coating or sheathing,such as paint, insulation, conversion coatings and the like; bare wiremay include some contaminants such as forming lubes, oils, soils and athin alumina layer formed by environmental oxidation, as well astemporary treatments applied for transport to reduce damage to wiresurfaces. Individual wires may have diameters ranging from about 0.05inches up to not more than 0.375 inches. Suitable wire diameters foroverhead conductor applications may be at least 1, 2, 3, 4 mm and notmore than about 10, 9, 8, 7, 6, 5 mm. In one example, the bare wire hasa diameter of 0.134 inches, although other wire diameters are alsocontemplated. Spool A in FIG. 3 is designated as a spool having barewire wound thereon.

In one embodiment, the bare wire is coated using a coating sub-processfor a wire, shown collectively as block 62. Processes according to theinvention may include a greater or fewer number of steps, differentvariations of a step, and various steps in the process may also beordered differently from the illustrated flow chart in otherembodiments. For example, bare wire having only minor amounts ofcontaminants on the wire surfaces, may be coated in the absence of apre-cleaning step or heavily contaminated wires may benefit from apre-clean step with several sub-steps such as cleaning, pickling andrinsing.

In FIG. 3, at step 64, spool “A” containing bare wire is connected to,e.g. placed in, or on, the coating apparatus (as described further belowwith reference to FIGS. 4 and 5). The bare wire end is fed through thecoating apparatus and connected to a spool B. Spool B is designated as aspool having coated wire thereon. A short section of wire on spool B maybe uncoated based on the initial setup of the apparatus beforeoperation, e.g. connection of the bare wire end to Spool B provides ashort initial length of uncoated wire on Spool B. In other embodiments,the bare wire is fed directly into the coating apparatus from anotherprocess, such as a metal forming or other metal treatment process, andthere is no feed spool, e.g. spool A, provided. Likewise, the coatedwire may be directly fed into other processing stations after coatinginstead of onto a collecting spool. In one example, the coatingapparatus is a sub-station in a cable winding operation and the coatedcable, with or without drying, is fed into a cable forming step, oranother process such that there is no collecting spool provided. Theforegoing integrated processes may be used provided that the currentrunning through the coating solution and the electrified wire does notinterfere with other operations and is not unfavorable from an economicor health and safety view. Alternatively, the coating process andapparatus may be operated independent of one or both of the wiregenerating operation and the cable forming operation.

At step 66, the wire in the apparatus is electrified to a high currentand a high voltage, as described herein, using an electrification devicesuch that the wire acts as an anode within the bath of a solutioncontaining chemical precursors for the coating. A cathode is providedwithin the bath. Both the electrification device and the cathode areelectrically connected to a power source, which when activated passescurrent to the wire via the electrification device, the electricalcurrent passing from the anodic wire through solution to the cathode.

At step 68, a motor is operated to feed wire through the bath to coatthe wire. The type of motor to be used is not particularly limited inany way, and can include for example an electric motor, an internalcombustion engine, motors based on pneumatic or hydraulic power or thelike. If only for economy, an electric motor is preferred. In oneembodiment, speed of the wire is adjustable based on a feedback loopproviding data on coating features, such as coating thickness measured,for example in real time or otherwise to a controller. In oneembodiment, a user interface is provided for monitoring wire speed,motor parameters and allows making changes to same with adjustmentand/or other devices associated with the apparatus.

At step 70, a cleaning device, such as a spray system, an acid oralkaline cleaning bath, ultrasound device, deoxidizing bath and/or anair knife, may be operated to clean the bare wire before it enters thesolution in the coating bath. In one example, a spray system provideshigh pressure deionized water to clean the wire. The cleaning processcan provide a better and more uniform substrate surface for coatingdeposition, and may also reduce introduction of debris or othercontaminants into the coating bath.

At step 72, the wire proceeding through the bath is coated via anelectrochemical process thereby providing a ceramic coating on thesurface of the wire. In one embodiment, the solution in the bath is anaqueous solution containing a coating precursor comprising a source oftitanium and a source of phosphorus. In one example, the aqueoussolution contains H₂TiF₆ and a source of phosphorus. An electro-ceramiccoating is deposited on the wire surface which comprises oxides ofmetals from the substrate and from the solution. In one embodiment, anoxide coating, which comprises aluminum oxide and titanium dioxide, isformed on the surface of the aluminum wire. Desirably, aluminum oxide ispresent in the coating in amounts of 1-25 wt. %, with the remaindercomprising titanium dioxide and non-zero, small amounts of elements fromthe bath. In one example, the coating includes aluminum oxide in anamount of at least, 5 weight percent, 10 weight percent, 15 weightpercent, 20 weight percent, or 25 weight percent, or 30 weight percentof the total weight of the high emissivity coating. In anotherrefinement, high emissivity electro-ceramic coating includes aluminumoxide in an amount of at most, 80 weight percent, 75 weight percent, 70weight percent, 60 weight percent, or 50 weight percent, or 40 weightpercent of the total weight of the high emissivity coating. Typically,the metal oxide or oxides other than aluminum oxide are present in anamount of at least 20 10, 15, 20, 25, 30, 35, 40, 45, or 50 weightpercent of the total weight of the high emissivity coating. In avariation, the aluminum oxide concentration varies over the thickness ofthe high emissivity coating being greater at the coating substrateinterface and generally decreasing as with increasing distances awayfrom the wire substrate. For example, the aluminum concentration may be10 to 50 percent higher at 0.1 microns from the interface than at 3, 5,7, or 10 microns from the interface.

In another embodiment, the emissivity of the coating is modified bychanges in the identity of the electroceramic coating precursors in theelectrolytic bath, e.g. precursor elements may include Ti, Zr, Zn, Hf,Sn, B, Al, Ge, Fe, Cu, Ce, Y, Bi, P, V, Nb, Mo, Mn, W and Co. In oneembodiment, features of the coating are adjusted by changing aluminumand/or zirconium concentration of the aqueous solution. The inclusion ofaluminum oxide and/or zirconium oxide advantageously allows theadjustment of coating features, e.g. the color and/or abrasionresistance of the high emissivity coating.

A visible glow or visible light discharge may occur along the surface ofthe wire as the coating is being formed. The electrochemical process maybe a plasma process. The wire may provide an anode connection withoxygen radicals reacting with titanium anions at the surface of the wireto form a titanium oxide, such as titania. Protons at the cathodeconnection in the bath may lead to formation of hydrogen gas as water inthe aqueous solution is electrolyzed, which desirably may be controlledand removed by one or more optional hoods or venting systems. In otherexamples, other chemical solutions may be used to provide a coated wire.

At step 74, a control system including a controller is used to controlthe speed of the motor, and the speed of the wire. By changing the speedof the wire, the residence time of the wire in the bath may becontrolled, thereby together with other process parameters, controllingthe thickness of the coating and the amount of dissolution of aluminumfrom the wire. Longer residence times for the wire may also be obtainedby for example, defining a longer path through the bath. The thicknessof the coating and/or the color of the coating may also be controlled bymodifying the wave form and/or voltage utilized. The control system isalso useful in adjusting spool speed for spools A and B. For wireprovided on a spool, to maintain a constant speed of wire travel throughthe bath as the wire is taken off of spool A, the rotational speed ofspool A may be increased to compensate for the smaller amount of wireprovided by each rotation. Likewise, as the coated wire accumulates onspool B, to maintain the same feed velocity of the wire, the rotationalspeed of spool B may be decreased to compensate for the greater amountof wire accumulated during each rotation around the increasingcircumference of spool B due to added coated wire. An accumulator, whichmay store up to perhaps 300 meters or more of wire ahead of the mainsection of the processing line, may be utilized to control wire speedand contact time in the bath. The control system may also control acooling system connected to the bath to cool the solution and maintainthe solution temperature within a predetermined range, desirably fromambient temperature, generally about 20 deg. Celsius to less than 100,95, 90, 80, 70, 60, 50 or 40 deg. Celsius.

At step 76, after the wire leaves the bath any excess solution remainingon the coated wire may be removed and desirably the coated wire may berinsed with water. In one embodiment, the excess solution, with orwithout rinse water can be returned to the bath in a recycling process.At step 78, the coated wire is collected onto spool B. When spool A isempty or near empty, the coating process 62 is stopped and spool Bcontaining coated wire is removed from the apparatus.

Although the coating process 62 is described for a single wire, multiplewires may be fed through the bath simultaneously, with each wire beingelectrified at a high power, as described herein. For simultaneouslycoating multiple wires, a minimum separation between the electrifiedwires should be maintained to avoid arcing and each wire may be providedwith separate electrification devices and guides as well as suppliedfrom and collected on separate spools. In alternative embodiments, acable, e.g. a wound bundle of wires, may be fed through the bath suchthat the outer surface wires and at least portions of the interior wiresof the cable are coated.

In one embodiment, the coated wires are polished after removal from thecoating apparatus. The polishing step serves to reduce surface roughnessand allows for easier handling of the coated wires during later bundlingsteps. The smoother surface is also less abrasive to uncoated innerwires of a cable, without significantly reducing surface area providedby the electrolytic coating.

At optional step 80, multiple spools of coated cable (spool B) areconnected to a cable winding or forming apparatus. The cable is formedby bundling and tensioning the wires to provide a predetermined degreeof twist to the various layers in the cable. The twist may be the samebetween various layers, may be twisted in opposed directions, or thedegree of twist vary from layer to layer. In one example, all of thewires in the cable are coated.

In another embodiment, only some or a portion of wires in the cable arecoated. At step 82, additional spools of uncoated or bare wire (spool A)may be provided to the cable forming apparatus. A spool of support wire,such as a steel wire, a composite wire, or the like, may also beprovided to add additional mechanical strength, such as tensile strengthor reduced sag characteristics, to the cable. The uncoated wires and thesupport wires are positioned to be internal wires within the cable. Thecoated wires are positioned to form the outer layer of the cable, or thelayer that provides the outer perimeter of the cable such that the cablepresents a coated outer surface to the environment. The cable is formedby bundling and tensioning the wires to provide a predetermined degreeof twist to the various layers in the cable, as described above.

In one embodiment, secondary heat transfer fins such as spine fins, orother durable fins that have a high surface area are also coatedaccording to the invention. These secondary heat transfer fins may bewound on a collecting spool, such as spool B and provided forapplication to the formed cable using an adhesive or the like, therebymultiplying the outer cable surface area and increasing emissivity.

At step 84, the cable is then provided onto a storage spool or reel. Thecable may be installed onto towers such as shown in FIG. 1 with variousconnectors and hardware as appropriate. The cable for use in overheadpower transmission is installed such that the coating on the cable isexposed to the environment, including solar radiation, or insolation.The cable for use in overhead power transmission does not have aninsulation sleeve, e.g. a sheath of polymer surrounding wires or thecable, provided on the cable when in use based on the operatingtemperatures of the cable.

FIG. 4 shows a schematic of one embodiment of an apparatus 100 forcontinuously coating a wire or strand, for example for use in the cable18 of FIGS. 1 and 2. Other configurations or layouts for the apparatus100 are contemplated based on the scale of the system, etc. Theapparatus 100 may also be used to directly coat a cable, such as cable18, in a similar manner as to that described below for the wire orstrand. In FIG. 4, a wire 102 runs from a first spool 104 to a secondspool 106. Each spool 104, 106 has a central barrel, or centercylindrical section, and may have flanges extending therefrom on eitherend of the central barrel. The first spool 104 provides a supply ofuncoated, bare wire, such as aluminum, useful for example in a hightension transmission cable, with the bare wire wound on the barrel ofthe spool 104. The second spool 106 receives the coated wire with thecoated wire being wound on the barrel of the spool 106. In otherembodiments, the wire may be continuously fed from and/or to anotherprocess such that there is not a first and/or second spool for theapparatus.

The wire 102 is fed through a bath 108 comprising a container at leastpartially filled with an aqueous solution comprising a precursor for aceramic coating on the wire. The container for the bath 108 may be madefrom a material that is chemically unreactive with the solution. Thecontainer for the bath may be electrically conductive to provide acathode, or may be made from electrically insulating and non-conductivematerial.

A first frame 110, or main frame, is supported above the bath 108. Inone example, the first frame 110 has a lower sub-frame 112, and firstand second end supports 114, 116. The frame 110 may be made fromnon-conductive materials, and in one example, the frame 110 iselectrically conductive. Legs or other support members may support theframe 110 on an underlying surface and above the bath 108, as shown orin other configurations.

The first spool 104 is supported by the frame 110 or the first endsupport 114 by a stationary shaft 128 or spindle. The spool 104 may beremoved from the shaft 128 as needed for operation of the apparatus. Afastener may connect with the end of the shaft 128 to retain the spool104 on the shaft 128 and allow for removal. The shaft 128 is positionedto be generally perpendicular with a section of the wire 102 as itleaves the spool 104, with the wire leaving the spool generallytangentially according to one example. A bearing assembly 130 isprovided between the spool 104 and the shaft 128. In one embodiment, thebearing assembly is within the cylindrical section of the spool 104 oron an outer section of the shaft 128 to reduce friction of the spool 104as it rotates about the shaft 128.

In this embodiment, an electric motor 132 is provided, and in FIG. 4 isshown on the second end support 116. The electric motor may be an ACmotor or DC motor. In other examples, the motor 132 may be anotherdevice, such as an internal combustion engine, a pneumatic or hydraulicmotor, or the like. The electric motor has an output shaft 136, whichmay form at least a portion of a motive assembly to drive the wire. Apad 134 made from an electrically insulating material is positionedbetween the electric motor 132 and the frame 110 such that the electricmotor 132 is electrically isolated from the frame 110. The pad 134 mayalso provide vibration damping. Electrically insulating material mayalso be positioned between the wire and the shafts or spindles 128, 136.The shafts and spindles 128, 136 may also be made from or coated with anelectrically insulating material. The container for the bath 108 mayalso be made from an electrically insulating material or include anelectrically insulating layer. The electrically insulating materialprevents conduction of the high voltage and high current.

The second spool 106 is supported by the output shaft 136 of theelectric motor 132. The spool 106 may be removed from the shaft 136 asneeded for operation of the apparatus. A fastener may connect with theend of the shaft 136 to retain the spool 106 on the shaft 136 and allowfor removal. The motor 132 shaft and the inner diameter of the spool 106may be keyed or splined such that they rotate together. A sleeve 138made of electrically insulating material is positioned within the barrelof the spool 106 such that the electric motor 132 is electricallyisolated froth the spool 106. Alternatively, the spool 106 may be madefrom an electrically insulating material.

In alternative embodiments, the electric motor 132 may be connected tothe first spool 104, or each spool 104, 106 may be provided with anelectric motor to impart movement to the wire 102 though the bath 108.Alternatively, the wire 102 may be moved using guides that are driven byone or more motors.

A second frame 140, or drop frame, is supported by the main frame 110and extends away from the main frame 110 such that it may be receivedwithin the bath 108. In other examples, the main frame 140 and dropframe 140 are separate components in the system and are not connected toone another. In one example, as shown, the second frame 140 is connectedto the lower sub-frame 112. The second frame 140 is positioned such thatit is partially submerged within solution in the bath 108. The secondframe 140 has at least one guide member 142 to guide the wire throughthe bath 108. In the example shown, the second frame 140 has first andsecond members 144 that extend from the first frame 110 with each framemember 144 having a guide member 142 connected to an end region. Eachguide member 142 may be a wheel connected to the frame member 144 by abearing connection, or may be a nonrotating guide member as is known inthe art. Desirably, the frame members 144 are made from an electricallyinsulating material or an electrically non-conductive material such thatelectrical current does not pass from the bath 108 to the main frame110. In one example, the frame members 144 or the frame 140 are madefrom plastic, such as a plastic or polymer, including, e.g. PVC, CPVC,polyethylene, polypropylene, polyamide, nylon, phenolic resin, as wellas non-conductive composites. The frame 140 and guide members 142 aremade from or coated with a material that is chemically inert ornonreactive with the solution in the bath. The frame 140 may beremovable from the bath 108 for maintenance and other operatingconsiderations.

In FIG. 4, an electrification device 146 is supported by the main frame110. In other embodiments, the device 146 may be supported by the frame140 adjacent to the bath 108. The electrification device 146 ispositioned to contact the wire 102, preferably near the bath 108; in theFigure the electrification device is above the bath 108. The device 146provides a dry anode connection to electrify the wire, and electrifiesthe entire length of the wire with a high voltage and a high current, asdescribed herein. The electrified wire 102 electrochemically reacts withthe solution in the bath 108 to form a coating on the wire whichcomprises metals from the wire as well as metals from the bath.

In one embodiment, the electrification device 146 may provide at least10, 20, 30, 40 or 50 kW per wire and higher provided that the conductorhas a great enough cross-sectional area to withstand the added kWwithout damage to the wire. Current density may be increased forpurposes of heating the wire in the bath to temperatures such that thecoating is applied and the wire is tempered in the same step in thebath. The electrification device may provide 50-60 kW to a single strandof wire in one example, and for a production system may provide 1, 2, 3,4, 5, 6, 8, 10 or more MW of power across multiple strands of wirerunning simultaneously through the bath 108. In a further embodiment,the device 146 is a rotary switch having a contact wheel that rotateswith passage of the wire 102 as the wire is fed from spool 104 to spool106. The rotary switch of the device 146 may have a liquid mercuryrotary contact, which is a rotating electrical connector with anelectrical connection made through a pool of liquid metal whichtransfers the electricity to the contact, thereby providing a lowresistance, stable connection. As the mercury contact rotates, theliquid metal maintains the electrical connection between the contactswithout wear and with low resistance. The liquid mercury rotary contactis able to provide the high voltage and high current needed to electrifythe wire 102. According to one example, the high voltage is a peakvoltage at or greater than 125 Volts.

High current is an effective current at or greater than about 20-1000Amps per wire. As wire size increases so does current carryingcapability without damage to the wire. Too much current through a wiremay result in excessive heating of the wire, resulting in embrittlementof the wire. Depending upon the gage of wire to be coated the amperagemay be adjusted to at least 20, 30, 40, 50, 60, 70, 80, 90, or 100 Ampsand preferably not more than 1000, 400, 300, 200 180, 160, 140, 120 Ampsper wire, i.e. a single strand of wire, for high tension wire. Appliedcurrent may be alternating current, asymmetric alternating current,direct current, or pulsed direct current. In some examples, directcurrent is used and may be applied as an on/off waveform. In oneembodiment, a total period of the waveform is at least 0.01, 0.1, 1 or10 milliseconds and up to 50, 40, 30, 20 or 15 milliseconds. Waveformsmay be adjusted to a ratio of at least: 0.1, 0.3, 0.6, 1.0, 1.2, 1.5,1.7, 2.0, 2.2, 2.5, 2.8, 3.0, 5.0, 10.0, or up to an infinite ratiowhere the direct current is always on and there is no off portion, alsoreferred to as straight DC.

In alternative embodiments, the electrification device 146 may comprisea rotating electrical connector, e.g. an electrical slip ring, brushedor brushless, or a liquid mercury rotary contact; or a non-rotating dryanode connection, e.g. an aluminum or copper contact surface, or otherdevices.

One or more cathode connections 148 are provided within the bath 108.The cathode connection 148 may be the container for the bath 108 itself,if the container is electrically conductive; or a component of suitablematerial, such as metal or graphite, positioned within the bath and incontact with the solution.

The electrification device 146 and the cathode connection 148 areconnected to a power supply 150. The power supply 150 may be controlledto provide direct current and/or alternating current to the anode andcathode or may provide asymmetric alternating current, for example, with400-500 Volts peak voltage at the anode, 40-50 Volts at the cathode. Insome embodiments, the power may be a square wave form pattern with afrequency of 0.01-40 milliseconds. In other examples, the power supplymay provide direct current or pulsed direct current to the anode andcathode. Frequency may be adjusted from 25 Hz to 25,000 Hz, may be highfrequency such as 200-25,000 Hz or 100-10,000 Hz. Waveforms may includesinusoidal, triangular, and/or rectangular in any of AC, DC or pulsed DCcurrent, as well as complex waveforms containing superimposed waveforms,e.g. an AC waveform over a DC waveform.

A cooling system 152 is in fluid communication with the bath to maintainthe temperature of the solution in the bath. In one example, the coolingsystem 152 maintains the solution at a predetermined temperature rangeby cooling the fluid. The temperature range may be greater than thefreezing point and less than the boiling point of the solution providedthat coating quality is not adversely affected. Generally useful rangesinclude zero to forty degrees Celsius, twenty to forty degrees Celsius,or other ranges as appropriate. As the wire is electrochemically coated,the solution is heated based on the reaction. The cooling system 152includes a heat exchanger and may include a pump to circulate and coolthe fluid. A fan or the like may be provided to direct air over the heatexchanger to cool the solution. In other embodiments, the solutioncontained within the bath 108 has sufficient thermal mass, or theelectrochemical process does not release sufficient heat to require acooling system 152.

In one example, at least one cleaning device 154 may be positioned tointeract with and clean the wire 102 before it enters the bath 108. Thecleaning device 154 may be supported by the frame 110. The cleaningdevice 154 may be a cleaning bath that chemically removes contaminantsor a physical cleaner which removes contaminants by physicalimpingement, e.g. abrasion, contacting with pressurized fluid, mediablasting, burnishing, or polishing, upon the wire. The cleaning device154 may be a spray system that sprays pressurized fluid across the wireas the wire is fed past the cleaning system to remove any debris orother undesirable material from the surface of the bare wire, such ascutting fluid, etc. The cleaning device 154 may also include a dip tank,and other cleaning systems as are known in the art for use with acontinuous system. In other examples, the bare wire is sufficientlyclean such that no cleaning device is needed for use with the apparatus100. In another example, a cleaning device 156 is positioned to interactwith the wire 102 after it exits the bath 108.

One or more sets of guides 158 may be provided on the first frame 110 orthe second frame 140 to guide the wire 102 to travel along apredetermined path between the first spool 104 and the second spool 106.The guides 158 may be roller guides, including one or two plane guides,or the like. The guides 158 may assist in directing the wire to pass bythe cleaning device 154 and/or the air knife 156. The guides 158 mayassist in a smooth feed of the wire from the first spool 104. The guides158 may also present the wire at the appropriate angle to the secondspool 106 for a smooth winding.

A controller 160 is in communication with the electric motor 132. Thecontroller 160 may be a single controller or multiple controllers incommunication with one another. The controller 160 may be connected torandom access memory or another data storage system. In someembodiments, the controller 160 has a user interface. The controller 160is configured to control the electric motor 132, the power supply 150,and the cooling system 152 for startup procedures, shut down procedures,and emergency stop procedures.

It is recognized that any circuit or other electrical device disclosedherein may include any number of microprocessors, integrated circuits,memory devices (e.g., FLASH, random access memory (RAM), read onlymemory (ROM), electrically programmable read only memory (EPROM),electrically erasable programmable read only memory (EEPROM), or othersuitable variants thereof) and software which co-act with one another toperform operation(s) disclosed herein. In addition, any one or more ofthe electrical devices as disclosed herein may be configured to executea computer-program that is embodied in a non-transitory computerreadable medium that is programmed to perform any number of thefunctions as disclosed herein.

In one embodiment, the controller 160 is in communication with a firstsensor 162 and a second sensor 164. The first and second sensors 162,164 are used with the first and second spools 104, 106, respectively.The first sensor 162 may be a speed and/or position sensor to determinethe rotational speed of the first spool 104 or the feed speed of thewire after it exits the spool 104. The first sensor 162 may also includean optical sensor or the like to determine the amount of wire on thefirst spool 104, for example, the outer diameter of the wire on thebarrel of the spool 104. The second sensor 164 may be a speed sensor forthe electric motor 132 that senses the rotational speed of the motorshaft, and corresponding speed and/or position of the spool 106. Thesecond sensor 164 may also include an optical sensor or the like todetermine the amount of wire on the second spool 106, for example, theouter diameter of the coated wire on the barrel of the spool 106.

The controller 160 controls the speed of the electric motor 132 tocontrol the speed of the second spool 106 and the feed speed of the wirethrough the apparatus. By controlling the feed speed of the wire 102,the residence time of the wire within the bath 108 is controlled. In oneembodiment, the controller 160 controls the motor 132 speed to maintaina residence time, meaning the total time on contact with the solution ofa given point on the wire, within a predetermined range or at apredetermined speed. Generally, residence time ranges from about 1, 2,3, 4, 5, 6, 8, or 10 seconds and at least for efficiency is not morethan 180, 160, 140, 120, 100, 60, 45, 30, 20 or 15 seconds. In oneexample, the residence time is approximately five to ten seconds.Generally, feed rate or wire speed is dependent upon achievingsufficient residence time for desired coating properties, e.g.thickness, surface area and emissivity, and desirably can range fromabout 10 feet per minute to about 200 feet per minute. Higher speeds maybe used provided that residence time is maintained. As the amount ofwire on the first spool 104 (and the diameter of the wrap of wire)decreases, the spool must spin faster to provide the same feed rate ofwire through the bath. Likewise, as the amount of wire on the secondspool 106 (and the diameter of the wrap of wire) increases, the spool106 must spin slower to provide the same feed rate of wire through thebath. Therefore, the controller 160 uses a closed or open control loopto constantly adjust and control the rotational speed of the electricmotor 132 to maintain a generally constant feed rate of wire andresidence time.

As the apparatus 100 is operated, bare wire leaves the spool 104 andtravels over the electrification device 146 and is electrified with ahigh current and a high voltage, as described herein, via a dry anodeconnection. The wire may be an aluminum or aluminum alloy wire in anembodiment. The bare wire then enters the bath 108. The wire iselectrified during contact with the bath. In one example, the bathcontains an aqueous electrolytic solution containing at least one of acomplex fluoride and an oxyfluoride. In other examples, other solutionsas disclosed herein may be used. The wire electrochemically reacts withthe precursor in the bath by passing a current between the wire in thebath and a cathode in the bath to form the coating. This reaction mayform a visible light-emitting discharge adjacent to the wire (or anoxygen plasma) and a hydrogen gas from the water in the aqueoussolution. The electrified wire may form a plasma with the liquidprecursor, with the bath acting as a cathode and the wire acting as ananode. A coating is formed on the bare wire, and the coating may be ametal/metalloid oxide electro-ceramic. The coating has an emissivitygreater than that of the bare wire. The thickness of the coating iscontrolled via control of various parameters including but not limitedto the residence time of the wire within the bath. The emissivity of thecoating may also be adjusted by changing the temperature of the solutionin the bath 108, and/or the power provided by the electrification device146 to a wire. In one embodiment, without changing the bath content, theemissivity can be increased by about 10, 20, 30, 40, or 50% bycontrolling deposition parameters including waveform, voltage, amperage,and contact time.

The continuous length of the wire 102 is electrified at a high currentand voltage, and a cathode is present in the bath 108 such that the wireacts as an anode in the bath 108. The first spool 104, the frame 110,and various guides or devices on the frame 110 may also be electrified.The second frame 140 is made of a non-conductive or insulating materialto prevent arcing, formation of the coating on the frame, and to reduceelectrical consumption by the apparatus. The electric motor 132 is alsoelectrically insulated from the frame 110 and the wire 102 to preventelectrical shorting of the motor 132.

The second spool of coated wire 102 may be removed from the apparatus100 and used to form, for example a transmission or distribution cable.Multiple spools of coated wire may be combined or bundled to form acable as shown in FIG. 2. Additionally, bare wire and/or support wiresmay be added to the cable assembly. In one example, bare wires andsupport wires are internal wires in the cable, and the coated wires formthe outer perimeter wires of the cable. The various wires of the cablemay be tensioned to provide a predetermined degree of twist. The cablemay be installed on a tower or in the electrical grid for use intransmitting voltage at least about 5 kV or more, and as such the outercoated surface of the cable formed by the coated wires interacts withthe environment to cool the cable by emitting radiation, includingradiation in the infrared wavelength.

FIGS. 5 and 6 are schematics of two exemplary embodiments of coatingsystem 210.

FIG. 5 is a side view schematic of a system 210. FIG. 6 is a top viewschematic of another system 210. Common reference numbers are used forsimilar components of the two schematics. The system 210 includes a feedspool 214 that contains uncoated wire, at least one coating bathcontainer 218 which during operation contains an electrolyte compositionE, and a take-up spool 216 that accepts coated wire. The wire 212travels from spool 214 to spool 216 through the bath 218. The apparatus210 may also be used to directly coat a cable, such as cable 18, in asimilar manner as to that described below for the wire.

Coating system 210 also includes at least one electrical power supply222 electrically connected to a cathode 224 located within coating bathcontainer 218, and to an electrification device 226 (dry anode) whichelectrifies uncoated wire 212 such that the wire 212 acts as an anode inthe electrolyte composition E, during operation.

Coating system 210 also includes at least one guide member 228 (twoshown in FIG. 5 and four shown in FIG. 6) used to guide uncoated wire212 through the electrolyte bath in container 218. Coating system 210includes roller guides 240 used to guide coated wire 212 as it exits theelectrolyte bath in container 218 and onto take-up spool 216. The rollerguides may also function to remove electrolyte carried out of the bathon coated wire 212.

Coating system 210 includes at least one motive device 232 which movesthe wire 212 through the coating system. The motive device 232 is notparticularly limited as long as it causes the wire 212 to move throughthe coating system 210. The motive device 232 typically includes a motorand a motive assembly; suitable motive assemblies may comprise acombination of a motor shaft, rotating guides, tensioning rollers,accumulators and the like. In one embodiment, the motive device 232 mayinclude an electric motor which moves the wire for example by rotatingthe take-up spool 216 via motor shaft 234 acting as a motive assembly,which may be the sole motive force for moving the wire 212 or may besupplemented by motors drawing the wire through the bath, for example byshoes or rotating guides propelling the wire along its path.

In some embodiments, as shown in FIG. 5, coating system 210 includes acooling system 250 in fluid communication with the electrolyte E in bathcontainer 218. The cooling system 250 may provide direct cooling to theelectrolyte E or may include a heat exchanger system or the like.

Coating system 210 also includes a controller 236 which is configured tocontrol at least one of the motive device 232, the power supply 222, andthe cooling system 250. In operation, the power supply 222 supplies theelectrification device 226 with a high voltage and current, as describedherein, which is provided to wire 212 when it is in proximity to theelectrification device 226, and generally in contact therewith. Wire 212is unwound from the feed spool 214, contacts the electrification device226, is electrified thereby and passes into the electrolyte E in bathcontainer 218. Wire 212 passes through the electrolyte E for a residencetime sufficient to electrolytically coat wire 212, then coated wire 212exits the electrolyte E, moves past or through drip guides 240 and iswound onto take-up spool 216. Coated wire 212 may optionally passthrough other stages before or after the electrolyte bath, for example apre-cleaning bath 260, a post rinsing bath 270 which may include apost-coating drying station 280, as shown in FIG. 5. One importantaspect of the invention is providing appropriate electrical insulationto parts of the coating system 232 which may be damaged by high voltageand current used for coating formation on the wire 212 or, for thoseparts of the system that do not require such high power, insulating orisolating them from the high power, at least for economy and safety.Hence, while feed spool 214, coating bath container 218, take-up spool216 and various guides are in contact with the electrified wire 212 orelectrolyte E, these parts may either be made of non-conductivematerials or physically insulated from other parts of the coatingsystem. For example, the electric motor portion of a motive device 232may be insulated from the electrified wire by interposing non-conductivecontact surfaces which impart movement to the wire 212, but do notconduct electricity back to the motor of the motive device. For example,electrically insulating material 230 may be used to isolate the wire212. Desirably, at least motors, pumps and the controller are insulatedor isolated such that they are not electrified by the high voltage andcurrent supplied to the electrification device 226 and the wire 212.

FIG. 5 additionally illustrates that more than one cathode 224 may beused in the bath 218, and the cathodes may be positioned to affectcoating properties, residence time, etc.

FIG. 6 additionally shows a complex path for the wire 212 through thesolution E in the bath 218. The guides 228 direct the wire 212 throughthe bath 218 for a longer residence time.

Various embodiments of the present disclosure have associated,non-limiting advantages. For example, the electro-ceramic coating on theouter stands or wires of the cable provides for increased emissivity ofthe cable and lower cable operating temperatures. By lowering the cableoperating temperature, the losses from the cable incurred by Jouleheating are reduced, and the cable sag is reduced. Also, by operatingthe cable at a lower temperature, the cable is able to transmit the sameamount of electrical power as an uncoated cable more efficiently, orgreater amounts of electrical power at the same operating temperature asthe uncoated cable. The apparatus and process for electro-ceramiccoating provides for continuous coating of a wire for use with thecable. The electrification device of the coating apparatus, such as arotating or non-rotating connector, provides the wire with a highvoltage and a high current, as described herein. The electrified wiretravels through a bath of liquid precursor, which in turn causes anelectrochemical reaction with the surface of the wire within the bath toform the coating. The frame supporting and guiding the wire through thebath may be made of an electrically insulating material to reduceoverall energy use by the apparatus and to prevent arcing. The electricmotor driving the wire through the bath may also be insulated to protectthe electric motor from the electrified wire.

While there have been described above the principles of this inventionin connection with specific apparatus, it is to be clearly understoodthat this description is made only by way of example and not as alimitation to the scope of the invention.

Additionally, the process and systems in the various embodimentsdescribed herein may be extended for use in coating other wire and/orcable for various applications. The coating may also be adjusted usingthe process as described herein to modify the thickness, porosity,color, emissivity, and other properties based on the desired applicationfor the wire and/or cable.

EXAMPLES Example 1

An aluminum alloy sample was coated in an aqueous electrolyticdeposition bath comprising 5.24 parts zirconium basic carbonate and20.06 parts hexafluorozirconic acid, at constant temperature and 410Volts peak for 3 minutes. A DC pulsed square waveform having an on/offratio of 1:3 was used. The coated sample was removed from the bath,rinsed with water and allowed to dry. Emissivity of the sample was 0.68at 3.1 microns thickness.

Example 2

An aluminum alloy sample was coated in an aqueous solution comprising 1part hexafluorotitanic acid and 1 part hexafluorozirconic acid to 0.375parts of a source of phosphate, measured as phosphate. The aqueoussolution was energised to 450 volts applied at constant temperature fora time sufficient to deposit an electroceramic coating. A DC pulsedsquare waveform having an on/off ratio of 2.78 was used. The coatedsample was removed from the bath, rinsed with water and allowed to dry.Emissivity of the sample was 0.79 at 9.0 microns.

Example 3

Aluminum alloy samples were coated in an electrolytic deposition bathcomprising a phosphate source and hexafluorotitanic acid at constantconcentration. All samples were coated in the same bath at constanttemperature. Voltage, amperage, time and waveforms were varied, as shownbelow. Waveforms for pulsed DC current were square. The coated sampleswere removed from the bath, rinsed with water and allowed to dry.Emissivity of the samples was determined for various combinations ofvoltage, amperage, time and waveforms used, and the results are shown inthe table below.

TABLE 1 Waveform Thickness and Time Variation (microns) on/off ratioVolts Amps (sec) Emissivity 1 1.41 DC on/off 250 185 12 0.41 ratio 2.782 3.03 DC on/off 290 185 12 0.52 ratio 2.78 3 3.23 DC on/off 320 185 120.58 ratio 2.78 4 4.85 DC on/off 370 185 12 0.6 ratio 2.78 5 6.32 DCon/off 410 185 12 0.62 ratio 2.78 6 7.99 DC on/off 475 185 12 0.62 ratio2.78 7 8.13 DC on/off 475 185 12 0.61 ratio 1.71 8 7 DC on/off 390 18512 0.59 ratio 1 9 6.75 DC on/off 475 185 12 0.61 ratio 1 10 8.4 StraightDC 390 147 12 0.64 11 10.25 Straight DC 475 147 12 0.62 12 13.34 Twostep AC 450 185 60 0.66 13 7.8 DC on/off 475 25 60 0.62 ratio 2.78 145.35 DC on/off 475 10 120 0.59 ratio 2.78 15 3.61 DC on/off 320 185 200.56 ratio 2.78 16 5.74 DC on/off 370 185 20 0.62 ratio 2.78 17 7.66 DCon/off 410 185 20 0.62 ratio 2.78 18 10.85 DC on/off 475 185 20 0.67ratio 2.78 19 9.84 DC on/off 475 185 20 0.65 ratio 1.71 20 6.24 DCon/off 390 185 20 0.6 ratio 1 21 7.89 DC on/off 475 185 20 0.62 ratio 122 7.03 Straight DC 390 147 20 0.63 23 11.18 Straight DC 475 147 20 0.68

The above results showed that without changing the bath content, theemissivity can be increased by about 40% from the lowest to the highestemissivity shown, by controlling deposition parameters includingwaveform, voltage, amperage, and contact time.

Example 4

An elemental depth profile was taken of the coatings of Example 3 usingglow discharge optical emission spectroscopy (GDOES). Amounts of variouselements were determined in weight percent at particular distances fromthe metal surface. For all samples, oxygen content built gradually frominitial values of less than 2 wt. % at the substrate, while the Alcontent dropped precipitously over a span of about 2 microns independentof coating thickness. Surface analyte weight percentages were similaracross the samples, as shown in the table below:

TABLE 2 Surface Al Surface Ti Surface O Surface P Variation Emissivity(wt. %) (wt. %) (wt. %) (wt. %) 1 0.41 <10  ~4 50-60 4-9 2 0.52 <10 ~10~74 4-9 3 0.58 <10 15-25 50-60 4-9 4 0.6 <10 15-25 50-60 4-9 5 0.62 <1015-25 50-60 4-9 6 0.62 <10 15-25 50-60 4-9 7 0.61 <10 15-25 50-60 4-9 80.59 <10 15-25 50-60 4-9 9 0.61 <10 ~28 50-60 4-9 10 0.64 <10 15-2550-60 4-9 11 0.62 <10 15-25 50-60 4-9 12 0.66 <10 15-25 60-70 4-9 130.62 <10 15-25 60-70 4-9 14 0.59 10 < x < 15 15-25 50-60 4-9 15 0.56 <10 ~4 60-70 4-9 16 0.62 <10 15-25 50-60 4-9 17 0.62 <10 15-25 50-60 4-9 180.67 <10 15-25 60-70 4-9 19 0.65 <10 15-25 60-70 4-9 20 0.6 <10 15-2550-60 4-9 21 0.62 <10 15-25 60-70 4-9 22 0.63 <10 15-25 50-60 4-9 230.68 <10 15-25 60-70 4-9

Comparing the data from the GDOES analysis of the coatings of Example 3showed surprising similarities between elemental profiles despitedifferent emissivity values. These results tend to show that coatingthickness, waveform of deposition, voltage and amperage worksynergistically to produce coatings, that although quite similarelementally, have differing emissivities.

Example 5

Aluminum alloy samples were coated in an electrolytic deposition bathcomprising a phosphate source and hexafluorotitanic acid at constantconcentration. All samples were coated in the same bath at constanttemperature and voltage. Time and waveforms were varied, as shown below.Waveforms for pulsed DC current were square. The coated samples wereremoved from the bath, rinsed with water and allowed to dry. Emissivityof the samples was determined for various combinations and the resultsare shown in the table below.

TABLE 3 Thickness Waveform Variation (microns) and on/off ratio Time(sec) Emissivity 24 9.4 DC on/off ratio 2.78 30 0.70 25 10 Straight DC30 0.71 26 9.4 DC on/off ratio 1 42 0.77

The above results showed that with bath content and voltage heldconstant, the emissivity was increased by about 10%, from the lowest tothe highest emissivity shown, by controlling waveform and contact time.

Example 6

Sets of commercially available aluminum alloy wires and representativeflat panel samples of the aluminum alloys were coated in electrolyticdeposition baths comprising a phosphate source and hexafluorotitanicacid at constant concentration. Voltage, power, time and waveforms werevaried, as shown below. Waveforms for pulsed DC current were square. Thecoated samples were removed from their baths, rinsed with water andallowed to dry. Quality and thickness of the coatings were assessed andthe results are shown in the table below.

TABLE 4 Thickness Measured Waveform Avg. kW Variation (microns)feet/minute on/off ratio Volts during run 27 7.3 10.0 1 450 30 28 6.634.0 1 450 32 29 8.9 22.7 2.78 450 39 30 8.3 26 2.78 450 42 31 8.2 312.78 475 62

The emissivity of the representative flat panel sample from the sameset, selected to have sufficient flat surface area for taking emissivityreadings, was measured. Emissivity of the flat samples was measured tobe 0.73±0.03. The above results showed that with bath content heldconstant, the emissivity can be maintained at a given level by selectingand/or controlling waveform, voltage, power, and contact time (for wirethis would generally be distance of travel per unit time through a bathalong a path of constant dimension, aka line speed).

Example 7

A series of aluminum alloy samples were electrolytically coated atconstant voltage of 435 V with a constant waveform having an on/offratio of 2.78, using the electrolyte of Example 3 which had beenmodified by the addition of dissolved Al, in amounts as shown in thetable below. The current applied and the coating time was held constantwithin each alloy group. The coated samples were removed from theelectrolyte, rinsed with water and allowed to air dry. The samples ineach alloy group were subjected to abrasion testing using a CS-10 gradeabrasive wheel under 500 gram load. After 5000 cycles of testing theweight loss and TWI were determined. Average values for both values areshown below.

TABLE 5 Average Weight Loss Al added to the coating Alloy (mg) AverageTWI bath (ppm)  713 8.51 1.70 10 14.66 2.93 450 17.46 3.49 860 A356 9.701.94 10 24.95 4.99 450 27.65 5.53 860 A380 7.45 1.49 10 17.65 3.53 45017.50 3.50 860 2024 14.10 2.82 10 22.30 4.46 450 24.20 4.84 860 606116.35 3.27 10 32.60 6.52 450 30.95 6.19 860 3003 19.00 3.80 10 27.955.59 450 27.60 5.52 860 5052 17.80 3.56 10 30.75 6.15 450 31.45 6.29 860

The above results show that adding Al to the electrolytic bath, changescoating features, e.g. the abrasion resistance and TWI of the resultingcoating.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the invention. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the invention.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the invention.

What is claimed is:
 1. A system for continuously electrolytically coating a wire for a high tension cable for use as an overhead transmission line, the system comprising components of: a bath for an aqueous electrolytic solution containing a precursor for an electro-ceramic coating on a wire; a first spool frame adapted to support a first spool for providing the wire to the bath; a second spool frame adapted to support a second spool for receiving the wire from the bath; an electrification device for electrifying the wire and located between the first spool frame and the bath; a plurality of guide members positioned to route the wire from the first spool to electrically engage with the electrification device, pass into, through and out of the bath, and be rewound around the second spool, wherein at least one of the plurality of guide members is a bath guide member removably fixed in position in the bath for routing the wire into contact with the aqueous electrolytic solution; at least one motor adapted to move the wire from the first spool, through the plurality of guide members and rewind the wire around the second spool; a cathodic connection positioned in the bath for contacting the aqueous electrolytic solution; and a power source electrically connected to the electrification device and the cathodic connection, said power source providing high voltage and high current to the wire through the electrification device, and through the wire in the bath to the cathode connection via the aqueous electrolytic solution; wherein the at least one motor is connected to at least one motive assembly capable of imparting movement from the motor to the wire.
 2. The system of claim 1 wherein the electrification device is a dry anode connection providing at least 25 kW per wire.
 3. The system of claim 1 wherein the electrification device comprises at least one of a rotating electrical connector and a non-rotating connection for imparting the high voltage and high current to the wire.
 4. The system of claim 1 wherein the electrification device comprises at least one of an electrical slip ring, a liquid mercury rotary contact and a non-rotating electrically conductive contact surface.
 5. The system of claim 1 wherein the motive assembly comprises at least one of the first spool, the second spool, and one or more of the plurality of guide members.
 6. The system of claim 1 wherein the motive assembly comprises one of the first and second spools connected to an output drive of one of the at least one motor.
 7. The system of claim 1 further comprising an electrically insulating material positioned between the at least one motor and the at least one motive assembly connected to said motor, and/or on a contact portion of the motive assembly for contacting the electrified wire.
 8. The system of claim 7 wherein the at least one motor is an electric motor and the electrically insulating material is positioned between the electric motor and the motive assembly for insulating the electric motor from the wire electrified by the electrification device.
 9. The system of claim 1 wherein the motive assembly comprises one or more of the plurality of guide members being a motive guide member connected to an output drive of one of the at least one motor, said motive guide member having one or more contact portions for contacting the wire and thereby imparting movement from the output drive to the wire.
 10. The system of claim 1 wherein at least one of the following components is comprised of an electrically insulating material: the bath; the first spool; the first spool frame; the second spool; the second spool frame; a support frame for the electrification device; at least one of the plurality of guide members; and the at least one motive assembly.
 11. The system of claim 10 wherein the first spool frame; the second spool frame; and the support frame for the electrification device are comprised of an electrically insulating material sufficient to prevent conduction of the high voltage and high current from the power source.
 12. The system of claim 1 wherein the components are configured, electrically insulated or electrically isolated such that arcing of the high voltage and high current from electrified components of the system or the electrified wire is prevented.
 13. The system of claim 1 further comprising a controller connected to and configured to control at least one of the at least one motor, the power supply, and an optional cooling system.
 14. The system of claim 13 further comprising a cooling system in fluid communication with the bath for cooling the aqueous electrolytic solution and at least partially comprised of an electrical insulating material for preventing conduction of the high voltage and high current.
 15. The system of claim 13 wherein the controller is connected to the motor and configured to control a speed of the motive assembly for controlling speed of the wire to maintain a residence time of the wire in the bath.
 16. The system of claim 1 wherein during use the electrified wire contacts the aqueous electrolytic solution, the high voltage and high current passes from the electrified wire acting as an anode to the cathodic connection, thereby forming a plasma around the wire with the precursor in the solution, resulting in electro-ceramic coating deposition.
 17. The system of claim 1 further comprising a cleaner station positioned between the bath and the second spool to remove excess liquid from the wire before the wire reaches the second spool.
 18. The system of claim 1 further comprising at least one of a cleaning device and a water spray positioned between at least one of the first spool and the bath and the second spool and the bath.
 19. The system of claim 1 wherein the precursor in the aqueous electrolytic solution comprises at least one of a complex metal fluoride and a metal oxyfluoride.
 20. The system of claim 1 wherein the first spool is provided with a bare wire comprising one of aluminum and an aluminum alloy which extends from the first spool to the electrification device, into the bath, out of the bath, and around the second spool.
 21. A process for forming a wire having a selected emissivity comprising: feeding bare wire through a bath having a cathodic connection and containing an aqueous solution comprising a precursor for an electro-ceramic coating; operating an electrification device in electrical communication with the bare wire thereby electrifying the bare wire with a high voltage and a high current; passing the electrified bare wire through the aqueous solution comprising a precursor for an electro-ceramic coating in the presence of the cathodic connection thereby passing current from the electrified bare wire through said aqueous solution to the cathodic connection; and electrochemically reacting the wire with the precursor for an electro-ceramic coating thereby generating a coated wire having an electro-ceramic coating on at least one surface.
 22. The process of claim 21 further comprising: controlling at least one of aqueous solution content, waveform, voltage, amperage, and contact time during a residence time of the electrified wire in the bath to thereby produce a selected emissivity on the coated wire having an electro-ceramic coating on at least one surface.
 23. The process of claim 21 wherein the waveform is pulsed DC and the process further comprises controlling the on/off ratio of the waveform.
 24. The process of claim 21 wherein the coating includes a metal/metalloid oxide electro-ceramic comprising aluminum oxide and titanium dioxide.
 25. The process of claim 21 wherein an emissivity of the coating is greater than an emissivity of the bare wire, measured under like conditions.
 26. The process of claim 21 wherein electrochemically reacting the wire with the precursor in the bath includes providing the wire as an anode and providing a cathode in the bath.
 27. The process of claim 26 wherein electrochemically reacting the wire forms a visible light-emitting discharge adjacent to immersed wire being coated.
 28. The process of claim 21 wherein the electrification device is a mercury rotary contact.
 29. The process of claim 21 further comprising: continuously collecting coated wire onto a second spool; and driving one of a first spool and the second spool to continuously feed bare wire from the first spool into the bath using an electric motor.
 30. The process of claim 21 further comprising supporting a first spool for bare wire, the electrification device, and an electric motor on a frame; and electrically insulating the electric motor from the frame and the wire.
 31. The process of claim 21 further comprising maintaining the aqueous solution at a temperature in a range of twenty to forty degrees Celsius.
 32. The process of claim 31 further comprising cooling the aqueous solution to maintain the temperature within the range.
 33. The process of claim 21 further comprising: continuously collecting coated wire onto a second spool; and controlling a speed of an output shaft of an electric motor to control a rotational speed of one of a first spool for bare wire and the second spool to maintain a residence time of the wire in the bath.
 34. The process of claim 21 wherein the residence time is five to 30 seconds.
 35. A coated metal wire or strip made according to the process of claim 21 wherein the coated metal wire or strip has a surface area that is at least 10 times greater than the bare metal wire or strip's surface area, preferably at least 10 times to about 1000 times greater than the bare metal wire or strip's surface area.
 36. The coated metal wire or strip of claim 36, wherein the coating comprises, titanium, oxygen and phosphorus, and optionally aluminum and/or zirconium and has a thickness being in a range of 1 to 50 microns.
 37. The coated metal wire or strip of claim 37 wherein aluminum oxide is present in the coating and aluminum oxide concentration is greater at an interface of the coating and the metal wire or strip and decreases with increasing distances away said interface.
 38. A system for continuously electrolytically coating a wire for a high tension cable for use as an overhead transmission line, the system comprising: a bath for an aqueous electrolytic solution containing a precursor for an electro-ceramic coating on a wire; an electrification device for electrifying the wire via a dry anode connection; a plurality of guide members positioned to route the wire to electrically engage the electrification device, pass into, through and out of the bath, wherein at least one of the plurality of guide members is a bath guide member removably fixed in position in the bath for routing the wire into contact with the aqueous electrolytic solution; a motor adapted to move the wire through the plurality of guide members; a cathodic connection positioned in the bath for contacting the aqueous electrolytic solution; and a power source electrically connected to the electrification device and the cathodic connection, said power source configured to provide high voltage and high current to the wire through the electrification device such that the wire and the cathode connection are in electrical communication in the bath via the aqueous electrolytic solution.
 39. The system of claim 38 further comprising an electrical insulator positioned to isolate the motor from an electrified wire.
 40. The system of claim 38 wherein the electrification device is a mercury rotary contact.
 41. The system of claim 38 wherein the bath guide member comprises an electrically insulating material. 